[PATCH] media: mali-c55: Serialise the ISP enable in the params and stats paths

[David Carlier <devnexen@gmail.com>]

Only the capture devices hold isp->capture_lock around the
mali_c55_pipeline_ready() check and the ISP enable or disable. When the
last two queues to start are on different video devices, both can see
a ready pipeline and both enable the ISP. The second call fails with
-EALREADY and its queue's start_streaming_called flag is cleared, so
the ISP is never disabled again and every later start fails.

Take capture_lock in the params and stats paths too.

Fixes: d5f281f3dd29 ("media: mali-c55: Add Mali-C55 ISP driver")
Cc: stable@vger.kernel.org
Signed-off-by: David Carlier <devnexen@gmail.com>
---
 drivers/media/platform/arm/mali-c55/mali-c55-params.c | 4 ++++
 drivers/media/platform/arm/mali-c55/mali-c55-stats.c  | 4 ++++
 2 files changed, 8 insertions(+)

diff --git a/drivers/media/platform/arm/mali-c55/mali-c55-params.c b/drivers/media/platform/arm/mali-c55/mali-c55-params.c
index 16e895e3488e..6515c78c1bb2 100644
--- a/drivers/media/platform/arm/mali-c55/mali-c55-params.c
+++ b/drivers/media/platform/arm/mali-c55/mali-c55-params.c
@@ -762,6 +762,8 @@ static int mali_c55_params_start_streaming(struct vb2_queue *q,
 	struct mali_c55 *mali_c55 = params->mali_c55;
 	int ret;
 
+	guard(mutex)(&mali_c55->isp.capture_lock);
+
 	ret = pm_runtime_resume_and_get(mali_c55->dev);
 	if (ret)
 		goto err_return_buffers;
@@ -796,6 +798,8 @@ static void mali_c55_params_stop_streaming(struct vb2_queue *q)
 	struct mali_c55 *mali_c55 = params->mali_c55;
 	struct mali_c55_isp *isp = &mali_c55->isp;
 
+	guard(mutex)(&isp->capture_lock);
+
 	if (mali_c55_pipeline_ready(mali_c55)) {
 		if (v4l2_subdev_is_streaming(&isp->sd))
 			v4l2_subdev_disable_streams(&isp->sd,
diff --git a/drivers/media/platform/arm/mali-c55/mali-c55-stats.c b/drivers/media/platform/arm/mali-c55/mali-c55-stats.c
index a9c28b090b2a..cbd2a2f77da3 100644
--- a/drivers/media/platform/arm/mali-c55/mali-c55-stats.c
+++ b/drivers/media/platform/arm/mali-c55/mali-c55-stats.c
@@ -146,6 +146,8 @@ static int mali_c55_stats_start_streaming(struct vb2_queue *q,
 	struct mali_c55 *mali_c55 = stats->mali_c55;
 	int ret;
 
+	guard(mutex)(&mali_c55->isp.capture_lock);
+
 	ret = pm_runtime_resume_and_get(mali_c55->dev);
 	if (ret)
 		goto err_return_buffers;
@@ -180,6 +182,8 @@ static void mali_c55_stats_stop_streaming(struct vb2_queue *q)
 	struct mali_c55 *mali_c55 = stats->mali_c55;
 	struct mali_c55_isp *isp = &mali_c55->isp;
 
+	guard(mutex)(&isp->capture_lock);
+
 	if (mali_c55_pipeline_ready(mali_c55)) {
 		if (v4l2_subdev_is_streaming(&isp->sd))
 			v4l2_subdev_disable_streams(&isp->sd,
-- 
2.55.0